Add: download_decisive_appraisal_pdf MCP tool

The PDF host (free-justice.openapi.gov.il) requires the same x-client-id
header as the search API, so a normal browser click on the URL fails.
This tool carries the auth header automatically and saves the PDF to a
configurable local directory.

Safety properties:
- SSRF guard: only download from free-justice.openapi.gov.il and
  pub-justice.openapi.gov.il.
- Path-traversal guard: filename is reduced to its basename; arbitrary
  paths are stripped.
- Content-type guard: rejects 200-OK responses whose body is not a real
  PDF (gateway sometimes returns JSON-error 200s).
- Atomic write via .tmp + rename so partial downloads never replace the
  cached copy.
- Caches by destination path; re-downloads are no-ops unless overwrite=True.

DECISIVE_APPRAISER_DOWNLOAD_DIR env var configures the output dir
(default: ./downloads/decisive_appraisals). 6 new unit tests cover the
happy path, caching, and all four guards. End-to-end live test confirmed
a 1.4MB real PDF lands on disk with valid `%PDF-1.7` header.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nadlan_mcp/fastmcp_server.py

@@ -1420,6 +1420,55 @@ def search_decisive_appraisals(
         return f"Error searching decisive appraisals: {str(e)}"
 
 
+@conditional_tool("tool_download_decisive_appraisal_pdf_enabled")
+def download_decisive_appraisal_pdf(
+    url: str,
+    filename: Optional[str] = None,
+    output_dir: Optional[str] = None,
+    overwrite: bool = False,
+) -> str:
+    """Download the PDF of a decisive-appraiser (שמאי מכריע) decision.
+
+    The PDF host requires the same `x-client-id` header as the search API,
+    so a normal browser click on the URL will fail. This tool carries the
+    auth header automatically.
+
+    Args:
+        url: Direct PDF URL, as returned in `decisions[].pdf_url` from
+            search_decisive_appraisals. Must be on free-justice.openapi.gov.il.
+        filename: Optional filename for the saved PDF. Path components are
+            stripped; only the basename is used. If omitted, a hash-based
+            filename is generated from the URL.
+        output_dir: Optional override for the output directory. Defaults to
+            the configured `DECISIVE_APPRAISER_DOWNLOAD_DIR`
+            (./downloads/decisive_appraisals).
+        overwrite: If False (default), returns the cached file when it
+            already exists at the destination.
+
+    Returns:
+        JSON string with `path` (absolute local file path), `size_bytes`,
+        `from_cache` (true if file already existed), `content_type`.
+    """
+    log_mcp_call(
+        "download_decisive_appraisal_pdf",
+        url=url,
+        filename=filename,
+        output_dir=output_dir,
+        overwrite=overwrite,
+    )
+    try:
+        result = decisive_appraiser_client.download_pdf(
+            url=url,
+            output_dir=output_dir,
+            filename=filename,
+            overwrite=overwrite,
+        )
+        return json.dumps(result, ensure_ascii=False, indent=None)
+    except Exception as e:
+        logger.error(f"Error in download_decisive_appraisal_pdf: {e}", exc_info=True)
+        return f"Error downloading appraisal PDF: {str(e)}"
+
+
 # Health check endpoint for HTTP deployments
 @mcp.custom_route("/health", methods=["GET"])
 async def health_check(request):